Sri Lanka's ex-president Rajapaksa sworn in as PM

The coronavirus can stay aloft for hours in tiny droplets in stagnant air, infecting people as they inhale, mounting scientific evidence suggests.

This risk is highest in crowded indoor spaces with poor ventilation, and may help explain superspreading events reported in meatpacking plants, churches and restaurants.

It’s unclear how often the virus is spread via these tiny droplets, or aerosols, compared with larger droplets that are expelled when a sick person coughs or sneezes, or transmitted through contact with contaminated surfaces, said Linsey Marr, an aerosol expert at Virginia Tech.

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Aerosols are released even when a person without symptoms exhales, talks or sings, according to Marr and more than 200 other experts, who have outlined the evidence in an open letter to the World Health Organization.

What is clear, they said, is that people should consider minimizing time indoors with people outside their families. Schools, nursing homes and businesses should consider adding powerful new air filters and ultraviolet lights that can kill airborne viruses.

What does it mean for a virus to be airborne?

For a virus to be airborne means that it can be carried through the air in a viable form. For most pathogens, this is a yes-no scenario. HIV, too delicate to survive outside the body, is not airborne. Measles is airborne, and dangerously so: It can survive in the air for up to two hours.

For the coronavirus, the definition has been more complicated. Experts agree that the virus does not travel long distances or remain viable outdoors. But evidence suggests it can traverse the length of a room and, in one set of experimental conditions, remain viable for perhaps three hours.

How are aerosols different from droplets?

Aerosols are droplets, droplets are aerosols — they do not differ except in size. Scientists sometimes refer to droplets fewer than 5 microns in diameter as aerosols. (By comparison, a red blood cell is about 5 microns in diameter; a human hair is about 50 microns wide.)

From the start of the pandemic, the WHO and other public health organizations have focused on the virus’s ability to spread through large droplets that are expelled when a symptomatic person coughs or sneezes.

These droplets are heavy, relatively speaking, and fall quickly to the floor or onto a surface that others might touch. This is why public health agencies have recommended maintaining a distance of at least 6 feet from others, and frequent hand washing.

But some experts have said for months that infected people also are releasing aerosols when they cough and sneeze. More important, they expel aerosols even when they breathe, talk or sing, especially with some exertion.

Scientists know now that people can spread the virus even in the absence of symptoms — without coughing or sneezing — and aerosols might explain that phenomenon.

Because aerosols are smaller, they contain much less virus than droplets do. But because they are lighter, they can linger in the air for hours, especially in the absence of fresh air. In a crowded indoor space, a single infected person can release enough aerosolized virus over time to infect many people, perhaps seeding a superspreader event.

For droplets to be responsible for that kind of spread, a single person would have to be within a few feet of all the other people, or to have contaminated an object that everyone else touched. All that seems unlikely to many experts: “I have to do too many mental gymnastics to explain those other routes of transmission compared to aerosol transmission, which is much simpler,” Marr said.

Can I stop worrying about physical distancing and washing my hands?

Physical distancing is still very important. The closer you are to an infected person, the more aerosols and droplets you may be exposed to. Washing your hands often is still a good idea.

What’s new is that those two things may not be enough. “We should be placing as much emphasis on masks and ventilation as we do with hand washing,” Marr said. “As far as we can tell, this is equally important, if not more important.”

Should I begin wearing a hospital-grade mask indoors? And how long is too long to stay indoors?

Health care workers may all need to wear N95 masks, which filter out most aerosols. At the moment, they are advised to do so only when engaged in certain medical procedures that are thought to produce aerosols.

For the rest of us, cloth face masks will still greatly reduce risk, as long as most people wear them. At home, when you’re with your own family or with roommates you know to be careful, masks are still not necessary. But it is a good idea to wear them in other indoor spaces, experts said.

As for how long is safe, that is frustratingly tough to answer. A lot depends on whether the room is too crowded to allow for a safe distance from others and whether there is fresh air circulating through the room.

What does airborne transmission mean for reopening schools and colleges?

This is a matter of intense debate. Many schools are poorly ventilated and are too poorly funded to invest in new filtration systems. “There is a huge vulnerability to infection transmission via aerosols in schools,” said Don Milton, an aerosol expert at the University of Maryland.

Most children younger than 12 seem to have only mild symptoms, if any, so elementary schools may get by. “So far, we don’t have evidence that elementary schools will be a problem, but the upper grades, I think, would be more likely to be a problem,” Milton said.

College dorms and classrooms are also cause for concern.

Milton said the government should think of long-term solutions for these problems. Having public schools closed “clogs up the whole economy, and it’s a major vulnerability,” he said.

“Until we understand how this is part of our national defense, and fund it appropriately, we’re going to remain extremely vulnerable to these kinds of biological threats.”

What are some things I can do to minimize the risks?

Do as much as you can outdoors. Despite the many photos of people at beaches, even a somewhat crowded beach, especially on a breezy day, is likely to be safer than a pub or an indoor restaurant with recycled air.

But even outdoors, wear a mask if you are likely to be close to others for an extended period.

When indoors, one simple thing people can do is to “open their windows and doors whenever possible,” Marr said. You can also upgrade the filters in your home air-conditioning systems, or adjust the settings to use more outdoor air rather than recirculated air.

Public buildings and businesses may want to invest in air purifiers and ultraviolet lights that can kill the virus. Despite their reputation, elevators may not be a big risk, Milton said, compared with public bathrooms or offices with stagnant air where you may spend a long time.

If none of those things are possible, try to minimize the time you spend in an indoor space, especially without a mask. The longer you spend inside, the greater the dose of virus you might inhale.

Rome, Mar 11: Italy has recorded its deadliest day of the coronavirus crisis despite locking down the entire country, as New York deployed the National Guard to contain a disease that has sown worldwide panic.

The hardest-hit country in Europe said its death toll from the COVID-19 virus had risen Tuesday by a third to 631, with the surging epidemic taking its toll on global sporting, cultural and political events.

While authorities in China, where the outbreak began, have declared it "basically curbed", cases are multiplying around the world, sparking panic buying in shops, and wild swings on financial markets.

China remains the hardest-hit overall with more than 80,000 cases and over 3,000 deaths, out of a global total of 117,339 cases and 4,251 deaths across 107 countries and territories, according to an AFP tally.

The virus is infecting all walks of life, including politics, with US Democratic presidential hopefuls Bernie Sanders and Joe Biden both cancelling campaign rallies and British health minister Nadine Dorries saying she had tested positive.

And amid criticism of the US authorities' response, New York deployed the National Guard for the first time during the crisis to help contain the spread of the disease from an infection-hit suburb.

There have been 173 confirmed cases in New York state, including 108 in Westchester County, home to New Rochelle where the majority of infections have been detected.

"It is a dramatic action, but it is the largest cluster in the country. This is literally a matter of life and death," said state governor Andrew Cuomo.

"People are scared, it's an unusual situation to be in," Miles Goldberg, who runs a New Rochelle bar, told AFP.

"It makes people nervous to be around others, it makes people nervous to get inside into businesses and such," he said.

In an unprecedented move, Italian Prime Minister Giuseppe Conte has told the 60 million residents of his country they should travel only for the most urgent work or health reasons.

And while squares in Milan and Rome were emptied of their usual bustle and traffic, some residents appeared uncertain if they were even allowed to leave their homes for everyday tasks like shopping.

The virus has battered tourism around the world, as people scrap travel plans, and a restaurant owner in Florence in northern Italy said that the impact on business had been catastrophic.

"We hope that we will see the end of it, because from around 140 covers a day, this afternoon, we've gone down to 20-25," Agostino Ferrara told AFP.

Pope Francis also seemed to muddy the waters, holding a mass in which he urged priests to go out and visit the sick -- something Conte has specifically discouraged.

Sporting events continued to fall victim to the virus as authorities urge people to avoid large gatherings.

Arsenal's game at Manchester City was postponed after players from the London club were put into quarantine, making it the first Premier League fixture to be called off because of the virus.

The virus has sparked doubts about the Olympics due to open in Tokyo on July 24 and the traditional flame lighting ceremony in Greece is set to be held without spectators.

In the United States, organisers rescheduled the two-week Coachella music festival for October.

The virus and the response to the crisis has prompted pandemonium on global markets with volatility not seen since the world financial crisis in 2008.

After suffering its worst session in more than 11 years at the beginning of the week, the Dow Jones Index in New York bounced back significantly, rising five percent on Tuesday.

Politicians around the world have scrambled to put together emergency packages to ease the significant financial hardships the virus is expected to cause for households and businesses.

US President Donald Trump, who is relying on a strong economy to boost his re-election hopes, promised to announce "major" economic measures on Tuesday.

The biggest item on his wish list is a cut in payroll taxes. But even allies in Congress and reportedly some aides in the White House are sceptical, questioning the cost.

Italy prepared Tuesday to let families skip mortgage and some tax payments while Japan unveiled a second emergency package to tackle economic woes stemming from the outbreak, including $15 billion in loan programmes to support small businesses.

Analysts warned of further volatility ahead however.

"It's like winding up a rubber band. The more you wind it, when you let go, the more it pops," said LBBW's Karl Haeling.

"A lot of the uncertainty goes to the root of the virus itself."

Washington, Jul 17: US President Donald Trump's economic adviser Larry Kudlow has said that TikTok may cut off ties to its Chinese parent and become a 100 per cent American company to circumvent demands to ban it as India has done.

"I think TikTok is going to pull out of the holding company which is China-run and operate as an independent American company," he told reporters at the White House on Thursday.

The US has not made a final decision on whether to ban it - which has been suggested by Secretary of State Mike Pompeo, he said.

TikTok being divested by ByteDance Technology Company "is a much better solution than banning or pushing away", said Kudlow, who is the Director of the National Economic Council.

He said that its services will be located in the US and "it will become an hundred per cent American company".

If it becomes a US company without Chinese links, India may have to reconsider the ban on the short video app wildly popular in the country.

India banned TikTok along with 58 other Chinese apps on June 29 citing threats to its defence and national security.

The ban came after a deadly clash between Indian and Chinese troops along the Line of Actual Control in Ladakh.

Under Beijing's National Security Law, all Chinese companies have to provide intelligence requested by the government, creating risks for users and their countries.

India was TikTok's biggest market outside of China, where it operates as Douyin.

There were about 200 million users in India and over 300 million downloads.

The US comes next with over 30 million users for the app.